“You shall make the Robe of the Ephod entirely of turquoise wool…. You shall make on its hem pomegranates of turquoise, purple, and scarlet wool, on its hem all around, and gold bells between them, all around; a gold bell and a pomegranate, a gold bell and a pomegranate on the hem of the robe, all around.“
One of the Vestements of the Kohen Gadol was the Meil, a robe that was adorned with bells and rang whenever the Kohen Gadol walked. The Gemara in Arachin discusses how all of the Kohen Gadol's Vestements atoned for a particular aveiro; the meil atoned for the sin of lashon hara. The Gemara explains that the meil, which made a loud kol (sound) should atone for lashon hara which makes a loud kol. However, the Gemara brings a seemingly contradictory braissa that says that the ketores (incense) that was used in the Mishkan atones for lashon hara. It answers that there are two different types of lashon hara; the ketores atones for a more 'quiet' form lashon hara, when the speaker hides his true feelings from the subject of his criticism and therefore the 'victim' of the lashon hara has no awareness that someone is criticizing him. In contrast, the lashon hara that is atoned for by the meil is characterized by the speaker making no secret of his true feelings about the victim to the extent that the victim is very likely to be aware of what is being said about him.
However, this explanation of the Gemara seems to pose a new difficulty; why is it necessary for there to be two separate functions of the Mishkan to atone for the single sin of lashon hara; why can't either the meil or the ketores atone for both 'loud' and 'quiet' lashon hara? Moreover, it would seem that loud lashon hara is significantly more damaging than 'quiet' lashon hara. Therefore, if the meil has the power to atone for the more severe form of lashon hara, then it should surely be able to atone for the seemingly less damaging 'quiet' lashon hara?
In order to answer this question it is necessary to understand more specifically the negative aspects of these two forms of lashon hara:
Loud lashon hara is very damaging in that the victim is aware of the evil speech that is directed towards him and this naturally causes him great pain. In this aspect, loud lashon hara is considered more destructive than its quieter counterpart. However, there is a certain way in which 'quiet' lashon hara is more pernicious than loud lashon hara.
Quiet lashon hara is characterized by the perpetrator of this grave sin behaving in a two-faced manner towards his victim; in front of him he is very friendly, but behind his back he slanders him mercilessly and instructs the listeners not to reveal his true feelings to his unfortunate fellow. Since the victim is totally unaware that he is being vilified, he makes no efforts to protect himself from these attacks and they may continue unabated. In contrast, the victim of 'loud' lashon hara is far more likely to find out about the lashon hara spoken about him, consequently he will be able to protect himself.
With this understanding we can now explain why it is necessary for there to be two separate functions of the Mishkan to atone for lashon hara. Each form of lashon hara is more detrimental in some way than the other. Consequently, whilst the meil has the capacity to atone for the damaging aspect of 'loud' lashon hara it cannot atone for the harm caused by quiet lashon hara. Similarly, the ketores can atone for the pernicious features of 'quiet' lashon hara but it cannot do so for the areas in which 'loud' lashon hara is more damaging.
What is particularly striking about this explanation is that in some ways speaking lashon hara in a hidden fashion is worse than doing so in a blatant manner. The Chofetz Chaim zt”l discusses how speaking lashon hara of the 'quiet' kind can also involve a transgression of the Mitzvo, “do not hate your brother in your heart (loh sisna es achicha bilvavecha).” The simple understanding of this Mitzvo is that one only transgresses it when he keeps his hatred in his heart and does not reveal it to anyone, including the subject of his hatred. However, if he expresses his hatred even in a negative way, he does not transgress 'loh sisna' because he did not keep the hatred in his heart.
The Chofetz Chaim argues that this is not necessarily the case; a person may hate his fellow and tells others of his hatred, but act towards him in a friendly manner. This, the Chofetz Chaim writes, is also a transgression of keeping hatred in one's heart. He explains that the root of the sin of keeping hatred in one's heart is that the subject of the hatred is unable to protect himself from the person who despises him. Consequently, if the 'hater' hides his true feelings to his fellow he is guilty of loh sisna even if he tells others about his hatred. We see from the Chofetz Chaim the above concept that 'quiet' lashon hara has a particularly insidious aspect to it, in that its victim is totally unable to protect himself from the silent bombardments that he is subjected to.
There may be occasions in a person's life where he develops a dislike for someone. It is self-evident that this loathing does not justify speaking lashon hara. We learn further from the Gemara in Arachin that acting towards him in a two-faced manner makes the lashon hara even more destructive.
Chazal tell us that Yosef's brothers were wrong in hating him, but to their credit they did not act in a hypocritical manner towards him. The lesson we derive from the brothers' behavior towards Yosef that whilst it is wrong to hate someone, it is far worse to hide that hatred of him and speak badly about him behind his back.
This hanhago only succeeds in causing enmity and machlokes. The ideal course of action is to try to resolve the situation by speaking to the subject of his hatred in a calm and reasonable manner and strive to resolve the issue in a mature fashion. By acting in an honest and candid manner, one can greatly improve his relationships with those around him.
Notes and Sources
 Tetzaveh, 28:31-34.
 A source that dates from the time of the Mishna.
 Arachin, 16a. My Rebbe, Rav Yitzchak Berkovits Shlita gave this explanation of what the Gemara meant by 'loud' and 'quiet' lashon hara.
 Kedoshim, 19:17.
 See Rambam, Hilchos Deos, Ch.6, Halachos 5-6; Ramban and Rashbam, Kedoshim, 19:17. Needless to say one is not permitted to express one's hatred in a hostile fashion, such as by shouting or striking his fellow Jew.
From The Book “The Guiding Light 2”